Health message for Monday, August 15: Unusually sensitive people should
consider reducing prolonged or heavy exertion outdoors.
Health message for Tuesday, August 16: Unusually sensitive people
should consider reducing prolonged or heavy exertion outdoors.
Synopsis and Discussion
OZONE: After being in the good range of the Air Quality Index the
previous four days, highest local ozone levels rose into the
mid-moderate range of the AQI on Sunday. Less afternoon cloud cover and
an outflow boundary from the north Saturday evening likely contributed
to this increase. Also of significance was that most of the higher
readings occurred over the central Valley rather than over the eastern
periphery; surface winds mostly <10 mph much of the day played a role in
this distribution. Forecast products are indicating that afternoon
gradient winds speeds will be below average beginning on Tuesday and
especially on Wednesday as an east to southeasterly component in the
10-18K' layer works its way downward. Thus, an increase in local ozone
production and accumulation is being forecast over the next few days -
perhaps reaching Ozone Health Watch criteria. This anticipated spike in
ozone concentrations could easily be delayed or prevented if convective
cloud debris lingers over the area during peak ozone production time.
Time will tell.
PARTICLES: Active summer monsoon weather will be mostly confined to the
higher terrain on the Valley's perimeter the next few days followed by
an upswing over the desert areas about Thursday. There is still the
potential for outflow boundaries from distant thunderstorms to generate
dust over the east and southeast portions of the metro area, but a low
risk is deemed appropriate thru Wednesday after which time the risk for
unhealthy PM-10 levels will climb.
For more information, please visit our Web page:
www.azdeq.gov/environ/air/ozone/ensemble.pdf
For transportation alternatives:
www.valleymetro.org
If you have any questions or comments regarding this forecast please
contact:
Arizona Department of Environmental Quality
Office of Communications
1110 W. Washington St., Phoenix, AZ 85007
(602) 771-2215
ms15@azdeq.gov